We evaluated the spatial distribution of otter trawl fishing effort and catches resulting from the imposition in 1994 of year-round and seasonal groundfish closed areas off the NE USA. Vessel locations were available from logbooks, vessel monitoring system (VMS) data from many of the largest vessels, and from observer records. There was high spatial coherence between VMS-and observer-derived trawling locations. Prior to establishment, 31% of trawl effort (1991e1993) occurred within the 22 000 km 2 of area that would eventually be closed year-round. In 2001e2003 about 10% of effort targeting groundfish was deployed within 1 km of the marine protected area (MPA) boundaries, and about 25% within 5 km. Density gradients, consistent with spill-over from MPAs, were apparent for some species. Average revenue per hour trawled was about twice as high within 4 km of the boundary, than for more distant catches, but the catch variability was greater nearer closed area boundaries. Seasonal closed areas attracted more fishing effort after opening than prior to closure even while average cpue was the same or lower. Spatial resolution of traditional data sources (e.g., logbooks) was too crude to discern detailed MPA-related effects, as revealed by high-resolution vessel positions from VMS and catch data obtained by observers.
Stock allocations derived from vessel monitoring system (VMS) positional data from northeastern U.S. fisheries were compared with those obtained from mandatory vessel trip report (VTR) logbooks. A gear-specific speed algorithm was applied to VMS positions collected in 2005 from otter trawl, Atlantic sea scallop Placopecten magellanicus dredge, sink gill-net, and benthic longline fisheries to estimate the locations of fishing activity. Estimated fishing locations were used to reallocate the stock area landings of eight federally managed groundfish species. The accuracy of the VMS method relative to that of the mandatory logbooks was assessed using haul locations and catch data recorded by at-sea observers. The VMS algorithm tended to overestimate the number of statistical areas fished, such that when a trip's fishing activity occurred in a single statistical area, logbooks more accurately reflected the true fishing location. However, when fishing activity occurred in multiple statistical areas, the VMS algorithm showed appreciable gains relative to logbook data. Compared with mandatory logbooks, the VMS method achieved distributions of stock landings closer to observer estimates in 77.8% of the cases examined. The stock allocation percentages from both the VMS-and VTR-based methods were within 1.7% for all stocks, suggesting that the impacts on total stock allocations are relatively minor. However, these small differences represent major relative differences in stock landings for less abundant stocks such as southern New England-Mid-Atlantic yellowtail flounder Limanda ferruginea, where the VTR-based method allocated 61.9% more landings than the VMSbased method. The VMS-based method is not a replacement for the VTR-based method; however, it can and should be used as a tool to identify those vessels for which targeted outreach activities would improve the accuracy of VTR statistical area reporting.
Atlantic cod (Gadus morhua) in the Georges Bank region have been commercially exploited since the 17th century and continue as the mainstay of the New England commercial and recreational groundfish fisheries today. Throughout most of its history, the Georges Bank cod fishery was unregulated and growth in the fishery did not appear to exceed resource potential. An historical review of assessment activities and management programs reveals that the Georges Bank cod stock seemed resilient to heavy fishing pressure until the early-and mid-1980s when landings, fishing effort and fishing mortality approached or attained record-high levels. Management plans enacted independently by the USA and Canada under extended fisheries jurisdiction have not been very successful in preventing overfishing of Georges Bank cod. Different management objectives and a lack of compatible management strategies and approaches between the two countries have exacerbated the situation. Both the USA and Canada now recognize that cooperative and coordinated management actions are needed to avert overfishing and rebuild transboundary fishery resources, including Georges Bank cod.
Recent experimental studies suggest that first-time spawning fish may not be as reproductively fit as repeat spawners. Traditional stock-recruitment models consider all mature fish as equivalent contributors to the spawning stock biomass. In this study we examine the effects of discounting first-time spawners on the stock-recruitment relationship of two species with varying life histories: Georges Bank haddock (Melanogrammus aeglefinus), a fast maturing gadoid, and Gulf of Maine witch flounder (Glyptocephalus cynoglossus), a slow maturing pleuronectid. Proportions of first-time spawning haddock ranged from 3 to 62 percent of the spawning stock biomass during 1963-96. Exclusion of all first-time spawners from spawning stock biomass improved the Ricker stock-recruitment relationship by 39 percent. For witch flounder, proportions of first-time spawners were less variable, never exceeding about 30 percent. Adjusting the spawning stock biomass for first-time spawners did not improved the overall relationship for witch flounder.
Independent research vessel surveys of the sea scallop resource on the northeastern part of Georges Bank were conducted annually by the USA and Canada during 1982-84. Despite differences between the USA and Canadian surveys in sampling design, statistically-comparable estimates of relative abundance, population size composition, and recruitment levels were obtained from the two surveys in each year. Four potential factors contributing to this concordance of results are identified and evaluated with respect to survey design considerations, sampling intensity and future survey activities. Because the information from the USA and Canadian surveys appears to be the same, there would be virtually no loss in accuracy or precision if survey responsibilities were shared on an alternate-year basis. Moreover, since survey ship time is costly, a considerable saving of expense would ensue to both countries from this arrangement.
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